/Engine/Source/Runtime/Engine/Public/ProfilingDebugging/LevelStreamingProfilingSubsystem.h
This subsystem captures level streaming operations for a specified time and outputs a .tsv (tab separated values) file to the profiling directory containing the amount of time spent loading levels and the time levels spent queuing for theability to load.
class ULevelStreamingProfilingSubsystem : public [UWorldSubsystem](API\Runtime\Engine\Subsystems\UWorldSubsystem)